Composition for prevention and/or treatment of tumors containing acacia bark derivative

ABSTRACT

It is intended to provide a composition which is useful in preventing or treating a tumor. The composition is a composition for the prevention and/or treatment of a tumor, containing an  acacia  bark derivative.

TECHNICAL FIELD

The present invention relates to a composition derived from a tree belonging to the genus Acacia for preventing and/or treating a tumor, and to uses of this composition as a food, an animal feed material and a medicine.

BACKGROUND ART

Although deaths caused by infections have decreased dramatically in Japan through the improvement in public health and the discovery of antibiotics and the like following the Second World War, the incidences of lifestyle diseases and particularly cancer have continued to increase in their place, with cancer having become the leading cause of death amongst Japanese in 1981. At present, about one out of every three persons dies of cancer. In addition, cancer is rapidly proliferating not only in Japan but in other countries as well, and is a disease that can be considered to be a common enemy of all persons.

Thus, the development of methods for preventing or treating tumors including cancer is considered to be an important and critical issue.

In actuality, although various anticancer drugs have been developed and are currently in use as therapeutic drugs, these have numerous problems, including the occurrence of serious adverse side effects.

With respect to acacia, acacia honey is known, and tannin which is extracted from bark thereof is known to be able to be used as a tanning agent or wood adhesive, while more recently, extracts of genus Acacia have been disclosed to have selective inhibitory effects on COX-2 (Patent Document 1), and bark of genus Acacia has been disclosed to have active oxygen elimination effects (Patent Document 2) and skin whitening effects due to the effect of inhibiting tyrosinase activity (Patent Document 3). However, acacia bark and polyphenols derived from acacia bark have heretofore not been confirmed to have an antitumor action.

-   [Patent Document 1] JP 2004-532811 A -   [Patent Document 2] JP 2004-352639 A -   [Patent Document 3] JP 10-025238 A

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

The object of the present invention is to provide an extremely safe composition that is useful for the prevention and/or treatment of tumors.

Means for Solving the Problems

As a result of conducting extensive studies to solve the above problems, the inventors of the present invention found that an acacia bark derivative has an excellent antitumor activity to be useful for the prevention or treatment of tumors, thereby leading to the completion of the present invention.

Namely, the present invention relates to a composition for the prevention and/or treatment of tumors, containing an acacia bark derivative(s).

In addition, the present invention also relates to a method for preventing or treating tumors using an acacia bark derivative(s).

Moreover, the present invention relates to a method for using an acacia bark derivative(s) for producing a composition for preventing or treating tumors.

Effects of the Invention

The composition of the present invention has an antitumor activity, and in particular, an excellent anti-malignant tumor activity.

In addition, the composition of the present invention is very safe and has less potential for adverse side effects and the like even if taken for a long period of time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing changes in live cell counts of YAC-1 cells.

FIG. 2 is a drawing showing the time schedule of a tumor growth inhibition test in mice.

FIG. 3 is a graph showing average tumor weights on day 28 after transplantation in mice.

BEST MODE FOR CARRYING OUT THE INVENTION

There are no particular limitations on the acacia bark derivative able to be used in the present invention provided that it is obtained by using as a raw material bark of a tree belonging to the genus Acacia (the tree is referred to as “acacia” or “genus Acacia” hereinafter), examples of which derivatives include a strip and a powder of acacia bark, and a suspension thereof, an extract such as a liquid extract, a concentrated liquid extract and a powdered extract of acacia bark, and a purified product obtained by purifying these extracts. The extract of acacia bark and particularly acacia bark polyphenols are preferable for giving an excellent antitumor activity.

In the present invention, only a single form of these acacia bark derivatives may be used, or alternatively two or more forms thereof may be used in combination.

Although there are no particular limitations on acacia able to be used in the present invention so long as it is a tree belonging to the genus Acacia, with respect to obtaining an acacia bark derivative having an excellent antitumor action, bark of the genus Acacia selected from the group consisting of scientific name: Acacia mearnsii De Wild. (generic name: black wattle), scientific name: Acacia mangium Willd. (generic name: acacia mangium), scientific name: Acacia dealbata Link, scientific name: Acacia decurrens Willd. and scientific name: Acacia pycnantha Benth. are preferable, while Acacia mearnsii De Wild. and Acacia mangium Willd. are particularly preferable.

In the present invention, only a single form of these acacia bark may be used, or alternatively two or more forms thereof may be used in combination.

The aforementioned acacia bark can normally be obtained by cutting down an acacia tree, pealing off only bark and then drying the bark more preferably by sun-drying.

Bark of acacia is comprised of an outer bark and a somewhat fibrous inner bark, and when dried to a moisture content of about 20% or less, can be easily finely pulverized with a size reduction mill such as a hammer mill. In the present invention, both the outer bark and inner bark of the genus Acacia may be used together or either one may be used alone as the acacia bark.

The aforementioned strip of acacia bark can be obtained in accordance with commonly used methods by pulverizing the acacia bark to a suitable size.

In addition, although the aforementioned powder of acacia bark can be obtained by pulverizing the acacia bark into a powder in accordance with commonly used methods, in particular, the particle diameter of the resulting powder is preferably 100 μm or less and particularly preferably 50 to 70 μm. Powder fractionation can be carried out by pulverizing the bark dried to a moisture content of 20% or less to a suitable size such as a particle diameter of about 1.6 mm or less, and then classifying the resulting powder with a vibrating screen or the like to obtain the required powder.

The aforementioned extract of acacia bark can be obtained by extraction from the acacia bark in accordance with commonly used methods. In order to obtain an extract of acacia bark having an excellent antitumor activity, it is preferably extracted from the acacia bark with an alcohol or a polar solvent.

Ethanol, etc. can be used as the alcohol, and water, etc. can be used as the polar solvent, and these solvents may be used singly or in combination of two or more kinds as necessary. A mixed solvent of water and the alcohol such as ethyl alcohol is particularly preferable for production of an excellent antitumor activity.

Moreover, the extraction procedure may be carried out a number of times using the same or different solvents.

An extract having an excellent antitumor activity can be obtained from the acacia bark by extraction with water or hot water, and then further extraction from the resulting extract with ethanol.

Although the extraction is carried out by adding the solvent to a strip, a powder or the like of the acacia bark followed by stirring as necessary, there are no particular limitations on temperature, time or solid-liquid ratio. In the case of using water as the solvent, the extraction may also be carried out with hot water. The resulting liquid extract may be freeze-dried or spray-dried directly, or may be freeze-dried or spray-dried after concentrating under reduced pressure. The resulting extract can be in various forms, such as a liquid extract, solution, powder, concentrate or paste, and can be used in a wide range of forms as necessary.

Moreover, the acacia bark extract of the present invention obtained in any of these forms can be used directly for the prevention or treatment of a tumor, or a purified product obtained by purifying the extract as necessary can also be used as an antitumor active ingredient.

In the present invention, ingredients contained in bark of the genus Acacia are also examples of the acacia bark derivatives. Examples of such ingredients are the acacia bark polyphenols. The acacia bark polyphenols are particularly preferable ingredients since they produce excellent antitumor activity.

The acacia bark polyphenols of the present invention refer to a type of condensed tannins in the form of polymers in which flavanols having as a basic skeleton flavan-3-ol such as (−)-fisetinidol, (−)-robinetinidol, (+)-catechin and (+)-gallocatechin are linked by C4-C8 or C4-C6 bonds. Here, the molecular weights of such condensed tannins are preferably 300 to 3000 and particularly preferably 500 to 3000. The acacia bark polyphenols used in the present invention can be obtained by extraction from the powder, etc. of the acacia bark with hot water as previously described.

In addition, examples of commercially available acacia bark polyphenols include MIMOSA ME POWDER, MIMOSA MS POWDER, MIMOSA GS POWDER, MIMOSA FS POWDER, MIMOSA WS POWDER, MIMOSA RG POWDER, MIMOSA RN POWDER, MIMOSA DK POWDER, MIMOSA AL POWDER, MIMOSA CR POWDER and GOLDEN MIMOSA POWDER (all registered trademarks) which are manufactured by Mimosa Central Co-operative Ltd., and the like.

Although the composition of the present invention may be the acacia bark derivative(s) such as the acacia bark, the extract(s) thereof, the purified product(s) thereof or the acacia bark polyphenol(s) per se, it may also contain other substance(s) having an antitumor activity, such as a substance useful in the prevention and/or treatment of tumors, examples of which include shark ointment, medicinal ginseng, caterpillar fungus, chitin, chitosan, agarisk, maitake, hardwood trunk rot, mekabu seaweed, mozuku seaweed and gulfweed.

Although the composition of the present invention may be the acacia bark derivative(s) such as the acacia bark, the extract(s) thereof, the purified product(s) thereof or the acacia bark polyphenol(s) per se, it may contain vehicles, sweeteners, sour flavorings, thickeners, fragrances, pigments, emulsifiers, and other additives or materials which are ordinarily used in drugs or foods, so long as they do not undermine the effects of the present invention.

Examples of tumors able to be prevented or treated with the composition of the present invention include benign or malignant tumors (cancers). Examples of benign tumors include pigmented nevus, dysplastic nevus, skin tag, lipoma, lymphangioma, seborrheic keratosis, dermatofibroma, keratoacanthoma, soft tissue tumors such as keloids, or polyps such as colorectal polyps or vocal cord polyps, while examples of malignant tumors include hematopoietic malignant tumors such as acute or chronic leukemia, malignant lymphoma, myeloma or macroglobulinemia; solid tumors such as a brain tumor, cancers of the head and neck (including laryngeal cancer, pharyngeal cancer and cancer of the tongue, etc.), breast cancer, lung cancer, esophageal cancer, gastric cancer, colorectal cancer, liver cancer, gallbladder and bile duct cancer, pancreatic cancer, renal cancer, adrenocortical cancer, bladder cancer, prostate cancer, testicular tumor, ovarian cancer, uterine cancer, choriocarcinoma, thyroid cancer, malignant cartinoid tumor, skin cancer, malignant melanoma, osteosarcoma, chondrosarcoma, soft tissue sarcoma, rhabdomyosarcoma, leiomyosarcoma, fibrosarcoma, liposarcoma or hemangiosarcoma; or cancers derived there from or associated therewith.

The composition of the invention of the present application is particularly useful for the prevention or treatment of leukemia, breast cancer, gastric cancer, colorectal cancer, liver cancer, renal cancer and hemangiosarcoma, and especially for the prevention or treatment of leukemia and breast cancer.

Furthermore, in the present invention, treatment includes shrinking or curing a tumor as well as inhibiting growth, metastasis or exacerbation of a tumor.

There are no particular limitations on an ingested amount of the composition according to the present invention, and the ingested amount can be suitably selected depending on the dosage form as well as the age, body weight and symptoms of an ingesting person such as a user or patient, or an ingesting animal. For example, it is desired that the ingesting person or ingesting animal orally ingests an amount of the acacia bark polyphenol(s) ranging from 0.001 to 1 g, preferably from 0.001 to 0.5 g and more preferably from 0.005 to 0.1 g per 1 kg of body weight per day in terms of the amount of active ingredient, since it produces an excellent antitumor activity.

The duration of ingestion can be arbitrarily determined depending on the age and symptoms of the user or patient.

The composition according to the present invention can be used as a food or an animal feed material, for example, as a health food, a functional food, a health supplement food, a food for specified health use, a beauty food or a nutritional supplement food (supplement). For example, these foods or animal feed material may also be in the form of a beverage such as tea or juice; ice cream, jelly, candy, chocolate or chewing gum, etc. In addition, they may also be in the form of liquids, powders, granules, capsules or tablets. Here, animals fed by the animal feed material include all animals requiring the prevention or treatment of tumors, including pets, livestock or animals bred at zoos, etc.

In addition, the composition according to the present invention can be used as a medicine or a guasi-drug. Although the medicine or guasi-drug can be administered, for example, orally in the form of powders, tablets, coated tablets, sugar coated pills, hard or soft gelatin capsules, liquids, emulsions or suspensions, they can also be administered rectally such as in the form of suppositories, topically or percutaneously such as in the form of ointments, creams, gels or liquids, or parenterally such as in the form of liquids for injection. However, they are preferably administered orally.

EXAMPLES

Although the following provides a more detailed explanation of the present invention through production examples, test examples and formulation examples thereof, the present invention is not limited thereto. In particular, although the following examples are indicated without making a distinction between the outer bark and inner bark of the acacia bark of the present invention, the outer bark can be separated from the inner bark and each can also be used, separately.

In the following production examples, test examples and the like, each acacia of the present invention is indicated with numbers shown in parentheses after each scientific name. For example, acacia known by the scientific name of Acacia mearnsii De Wild. is indicated as Acacia No. 1.

Scientific name: Acacia mearnsii De Wild. (No. 1), scientific name: Acacia mangium Willd. (No. 2), scientific name: Acacia dealbata Link (No. 3), scientific name: Acacia decurrens Willd. (No. 4), scientific name: Acacia pycnantha Benth. (No. 5).

In addition, percentages (%) refer to percent by weight (wt %) unless specifically indicated otherwise.

Production Example 1 Acacia Bark Powder

Bark of Acacia No. 1 was dried to a moisture content of 20% or less and after pulverizing the dried bark in a hammer mill to a powder having a particle diameter of 1.6 mm or less (the powder passing through a 10 mesh Tyler screen), the powder was further classified with a vibrating screen to obtain a fine powder having a particle diameter of 63 μm or less (passing through a 250 mesh screen).

Fine powders each having a particle diameter of 63 μm or less were similarly obtained by pulverizing bark of the remaining four types of acacia namely Acacia No. 2 to Acacia No. 5. Although there were some differences in the efficiency by which the fine powder passed through the 250 mesh screen depending on the type, all of the target fine powders were able to be obtained.

Production Example 2 Acacia Bark Extract

Bark of each Acacia No. 1 to 5 of the present invention was dried to a moisture content of 20% or less and after pulverizing the dried bark in a hammer mill to a powder having a particle diameter of 1.6 mm or less, five times the amount of hot water were added to 100 g of the dried pulverized bark followed by extraction for 15 minutes after boiling, and then filtering using a 10 to 20 μm filter. The resulting filtrate was spray-dried in a spray dryer to obtain 40 g of each bark extract.

The bark extracts are hereinafter indicated as Acacia Hot Water Extracts Nos. 1 to 5, respectively.

Production Example 3 Acacia Bark Extract

Acacia bark of the present invention was dried to a moisture content of 20% or less and after pulverizing the dried bark in a hammer mill to a powder having a particle diameter of 1.6 mm or less, five times the amount of ethanol were added to 100 g of the dried pulverized bark followed by extraction for 15 minutes while refluxing after boiling, and then filtering using a 10 to 20 μm filter. After evaporating the ethanol from the resulting filtrate, the concentrate was spray-dried in a closed spray dryer to obtain 40 g of bark extract (to be indicated hereinafter in the manner of Acacia Ethanol Extract No. 1).

Acacia Ethanol Extracts Nos. 1 to 5 were obtained in the same manner.

Production Example 4 Acacia Bark Extract

Three times the amount of ethanol were added to 10 g of the acacia hot water extract obtained in Production Example 2 followed by extraction for 15 minutes while refluxing after boiling, and then filtering using a 10 to 20 μm filter. The ethanol was evaporated from the resulting filtrate, water was added thereto, and then freeze-dried to obtain 9 g of extract (to be indicated hereinafter in the manner of Acacia Hot Water Extract Ethanol Fraction No. 1).

Acacia Hot Water Extract Ethanol fractions Nos. 1 to 5 were obtained in the same manner.

Test Example 1 Growth Inhibitory Effects During In Vitro Culturing of Tumor Cells

(1) Preparation of Test Samples

2 mL of distilled water were added to 200 mg of Acacia Hot Water Extract No. 1 described in Production Example 2 followed by extraction for 10 minutes at 100° C. The extract was filtered (Millipore filter, pore diameter: 0.45 μm) and the filtrate was diluted 10-fold and 100-fold with 10% FCS-RPMI 1640 to prepare test samples in which the concentrations of Acacia Hot Water Extract No. 1 were 10 mg/mL and 1 mg/mL, respectively (the concentration was indicated as the raw material equivalent).

In addition, 2 mg of mitomycin C was diluted with 10% FCS-RPMI 1640 to prepare a 50 μg/mL solution for use as an effective control.

(2) Materials and Methods

Mouse leukemia cells YAC-1 (provided by Riken Cell Bank) were subcultured, and cells obtained on day 4 of subculturing were suspended in 10% FCS-RPMI 1640 at 1×10⁶ cells/mL.

950 μL of the above YAC-1 cells (1×10⁶ cells/mL) were injected into each well of a 24-well plate followed by addition of 50 μL of the test samples prepared above, agitating and culturing for 3 days at 37° C. Following culturing, cell counts and survival rates were measured to determine the live cell counts.

(3) Results

When test samples of Acacia Hot Water Extract No. 1 were added, the growth of YAC-1 cells was inhibited, and at a concentration of 0.5 mg/ml in particular, YAC-1 cell growth inhibitory action was demonstrated to be greater than that at a concentration of 5.0 mg/mL or that of mitomycin C (concentration: 2.5 μg/mL) (FIG. 1).

Test Example 2 Tumor Growth Inhibition Test in Mice

(1) Test Method

The required weighed amounts of Acacia Hot Water Extract No. 1 described in Production Example 2 were dispersed in water at 60° C. to prepare test drinks 1, 2 and 3 containing Acacia Hot Water Extract No. 1 at 7.8 mg/mL, 15.6 mg/mL and 31.3 mg/mL, respectively.

The required weighed amounts of Acacia Hot Water Extract No. 1 described in Production Example 2 were mixed with commercially available feed to prepare test feeds 2 and 3 containing Acacia Hot Water Extract No. 1 at 15.6 mg/g and 31.3 mg/g, respectively.

Female C3H/HeN mice were assigned to a Control 1 group, Test 1 group, Test 2 group, Test 3 group and Positive Control group as shown in the table below.

TABLE 1 Grouping Days 1 to 6 of Transplantation Days 7 to 28 of Transplantation Drinking water and feed Drinking water and feed No. of or administered No. of or administered Group animals substance Group animals substance Control 1 10 Tap water + Control 1 10 Tap water + group control feed group control feed Test 1 10 Test drink 1 + Test 1 10 Test drink 1 + group control feed group control feed Test 2 group 10 Test drink 2 + control feed

Control 2 group Test 2a group  4*    5 Tap water + control feed Tap water + test feed 2 Test 3 group 10 Test drink 3 + control feed

Control 3 group Test 3a group  5    5 Tap water + control feed Tap water + test feed 3 Positive  5 Tap water + Positive  5 Tap water + Control control feed Control control feed + group group lentinan *Four animals were used since one of the animals died prior to day 4 of transplantation.

The test was carried out according to the time schedule shown in FIG. 2.

First, 2×10⁶ mouse tumor MM46 breast cancer cells were transplanted subcutaneously into the inguinal region of the mice grouped as indicated above according to the method described in Abe, S. et al., Gann 73, 91-96 (1982) and Ohasi, K. et al., Yakugaku Zasshi 113, 396-399 (1993).

Tap water was given to the Control 1 group while Test Drinks 1 to 3 were given to the Test 1 to Test 3 groups, respectively, as drinking water, starting on the day of tumor transplantation. In addition, tap water was given to the Positive Control group, and this group was also intraperitoneally administered 6.25 mg/kg of lentinan on days 7, 11 and 14 following tumor transplantation.

Water consumption in the Test 2 group and Test 3 group was 0.2 mL/day, which was much lower than that of the other groups at 4 to 6 mL/day, and the animals of the former groups also exhibited prominent weight loss. Consequently, Test Drink 2 and Test Drink 3 were replaced with tap water on day 7 of tumor transplantation. In addition, five mice each of the Test 2 group were reassigned to a Control 2 group and a Test 2a group, while five mice each of the Test 3 group were reassigned to a Control 3 group and a Test 3a group. Animals of the Control 2 group and Control 3 group were continued to be fed the control feed. The Test 2a group and Test 3a group were fed Test Feed 2 and Test Feed 3, respectively, instead of the control feed.

Growth of the tumor transplanted subcutaneously into the inguinal regions of the mice was observed by palpation for 4 weeks every 3 or 4 days, and tumor diameter was also measured. In addition, survival times (days) and body weights were also measured. The tumors were excised and their wet weights were measured following completion of the test.

(2) Test Results

The results are shown in Table 2 and FIG. 3. Furthermore, the Student's t-test was used for statistical testing.

TABLE 2 Action on Average Tumor Diameter Day 28 after Dose group Day 14 after transplantation transplantation Control 1 group 13.1 ± 3.93 23.8 ± 5.29 Test 1 group 10.5 ± 4.03 (19.8)^(a) 19.6 ± 3.92 (17.6)^(a) Control 2 group 12.2 ± 0.84 22.0 ± 2.74 Test 2a group 13.0 ± 1.15 (−6.56)^(b) 24.8 ± 1.50 (−12.7)^(b) Control 3 group 13.0 ± 1.73 28.2 ± 1.30 Test 3a group 10.2 ± 1.79 (21.5)^(c) 20.6 ± 2.97* (27.0)^(c) Positive Control  7.4 ± 6.58 (43.5)^(a) 14.0 ± 6.12 (41.2)^(a) group Units: mm ^(a)Indicates reduction rate (%) versus Control 1 group. ^(b)Indicates reduction rate (%) versus Control 2 group. ^(c)Indicates reduction rate (%) versus Control 3 group. *Indicates P < 0.05 versus Control 3 group.

On the basis of the above, the acacia bark was determined to inhibit growth of leukemia cells and breast cancer, and was observed to have an anti-tumor activity.

In the Test 1 group and Test 3a group, tumors were inhibited starting on day 14 after transplantation, and the anti-tumor action of the acacia bark was observed to appear rapidly.

In the Test 2 group and Test 3 group, although decreases in water consumption were observed, this was thought to be due to the strong bitter taste of the test drinks containing high concentrations of the acacia bark. When the test drinks were replaced with tap water and instead the test feeds were given, body weights were observed to recover, thus indicating that the weight loss was not attributable to toxicity of the acacia bark.

Test Example 3 Mutagenicity Test

A mutagenicity test was conducted in compliance with the Ministry of Health, Labor and Welfare Notification No. 77 (Sep. 1, 1988). As a result of testing with test substance (Acacia Hot Water Extracts Nos. 1 to 5 of Production Example 2) at doses of 156 to 5,000 μg/plate, there were no increases in the numbers of revertant colonies for any of the bacterial strains.

Test Example 4 Micronucleus Test

The presence of the ability to induce micronuclei was investigated in vivo in accordance with ordinary methods. Acacia Hot Water Extract No. 1 was orally administered twice at 24-hour intervals at daily doses of 2,000, 1,000 and 500 mg/kg to male ICR mice followed by the preparation of micronucleus specimens 24 hours after the final dosing.

Acacia Hot Water Extract No. 1 did not demonstrate positive results at any of the dose levels. In addition, there were no constant fluctuations in the simultaneously observed ratio of total polychromatic erythrocytes to total erythrocytes, and inhibition of erythrocyte proliferation was not observed in comparisons with a negative control group.

Test Example 5 Mouse Acute Toxicity Study (Oral Administration)

An acute oral dose toxicity study was conducted using male and female ICR mice in compliance with OECD (Guidelines for the Testing of Chemicals, 401, 1987). As a result, the LD₅₀ value of Acacia Hot Water Extract No. 1 was 4,468 mg/kg among males and 3,594 mg/kg among females.

Similar results were obtained in the above study for Acacia Hot Water Extracts Nos. 2 to 5 of Production Example 2.

Test Example 6 Rat Repeated Dose Toxicity Study (Oral Administration)

A 13-week repeated dose toxicity study was conducted using rats in accordance with ordinary methods. Mixed feed containing 0.5, 1.5 and 5.0% of Acacia Hot Water Extract No. 1 was fed to male and female Slc:SD rats.

As a result, none of the rats died or demonstrated abnormalities in examinations, including general condition.

Test Example 7 Human Single Dose Study

Five healthy adult males age 32 to 43 years were given 1500 mg of Acacia Hot Water Extract No. 1 (12 tablets of Formulation Example 4 described below). Although general examinations, hematology tests, blood biochemistry tests and urinalyses were performed on the subjects before ingestion, 3 hours after ingestion, 8 hours after ingestion, 24 hours after ingestion and 1 week after ingestion, there were no clinically significant fluctuations in test values. There were also no adverse events attributable to the tablets.

Test Example 8 Human 4-Week Continuous Dosing Study

Twenty-five healthy adult males age 23 to 44 years were given Acacia Hot Water Extract No. 1 of Formulation Example 4 described below at 750 mg/day (6 tablets of Formulation Example 4) and 1000 mg/day (8 tablets of Formulation Example 4) for 4 weeks each.

General examinations, hematology tests and urinalyses were performed on the subjects of each group before ingestion, 2 weeks after ingestion, 4 weeks after ingestion and 2 weeks following completion of ingestion. There were no clinically significant fluctuations in test values. There were also no adverse events.

Formulation Example 1 Preparation of Internal Medication

An internal medication having the composition indicated below was prepared using the acacia bark Hot Water Extract Ethanol Fraction of Production Example 4.

Extract fraction of Production Example 4 1.0 (wt %) Lactose 30.0 Cornstarch 60.0 Crystalline cellulose 8.0 Polyvinyl pyrrolidone 1.0 Total 100.0

Formulation Example 2 Preparation of Pet Food

A pet food having the composition indicated below was prepared using the acacia bark Hot Water Extract of Production Example 2.

Extract of Production Example 2 1.0 (wt %) Oatmeal 88.0 Starch 5.0 Salt 2.5 Whole egg 3.0 Flavoring 0.5 Total 100.0

Formulation Example 3 Preparation of Tablets (Confections)

Tablets (confections) having the composition indicated below were prepared using the acacia bark Hot Water Extract Ethanol Fraction of Production Example 4.

Extract fraction of Production Example 4 1.0 (wt %) Citric acid 1.0 Powdered skim milk 15.0 Sucrose ester 1.0 Flavoring 0.5 Powdered sugar 20.0 Lactose 61.5 Total 100.0

Formulation Example 4 Preparation of Tablets

Tablets having the composition indicated below were prepared using Acacia Bark Hot Water Extract No. 1 of Production Example 2.

Acacia Bark Hot Water Extract No. 1 of 125 (mg) Production Example 2 Sucrose ester 9 Lactose 166 Total 300

INDUSTRIAL APPLICABILITY

According to the present invention, a composition for preventing and/or treating a tumor can be obtained.

More specifically, the composition of the present invention is useful for preventing and/or treating various types of benign or malignant tumors.

The composition can be used as a medicine, a guasi-drug or a cosmetic, or a food or an animal feed material such as a health food, a health supplement food, a food for specified health use or a nutritional supplement food. 

The invention claimed is:
 1. A method of treating leukemia comprising administering to a subject in need thereof a composition consisting of: (a) a hot water extract(s) of Acacia bark, wherein the Acacia bark comprises at least one bark selected from Acacia mearnsii De Wild., Acacia mangium Willd., Acacia dealbata Link, Acacia decurrens Willd, and Acacia pvcnantha Benth; and (b) optionally, at least one of black vinegar, onion extract, yacon, a pharmaceutical vehicle, a sweetener, a flavoring, a thickener, a fragrance, a pigment, and an emulsifier.
 2. The method of claim 1, wherein the Acacia bark comprises at least one bark selected from the group consisting of Acacia mearnsii De Wild. and Acacia mangium Willd.
 3. The method of claim 1, wherein the Acacia bark is a bark of Acacia mearnsii De Wild.
 4. The method of claim 1, wherein the hot water extract(s) of acacia bark is an acacia bark polyphenol(s).
 5. The method of claim 1, wherein the composition is a food.
 6. The method of claim 4, wherein the acacia bark polyphenol(s) is a condensed tannin(s).
 7. The method of claim 4, wherein the acacia bark polyphenol(s) is administered orally at 0.001 to 1 g per kg of body weight per day in terms of the amount of active ingredient.
 8. The method of claim 6, wherein the condensed tannin(s) has a molecular weight(s) of 500 to
 3000. 9. The method of claim 6, wherein the condensed tannin(s) is a polymer(s) of flavanols having flavan-3-ol as a basic skeleton. 